Scientists quantify number of human deaths due to antibiotic use in chicken production

05 August 2013

Approximately 280 people are dying every year in the UK from blood infections caused by a highly antibiotic-resistant E. coli superbug, acquired from chicken. According to a new study, poultry-associated ESBL E. coli infections in the UK result in an additional 12,500 days in hospital for treatment with antibiotics of last resort and throughout the EU as a whole, 8,502 cases of blood-poisoning and 1,519 deaths every year specifically linked to chicken production.

ESBL (extended spectrum beta lactamase) E. coli have become an increasing problem on farms and in human medicine over the last decade. The resistance is caused by modern antibiotics known as third and fourth generation cephalosporins. These are used in both farming and in hospitals making it difficult to work out how much of the problem arises from each sector.

In the first study of its kind, an international team of scientists used a Dutch genetic fingerprinting study to estimate the proportion of ESBL E.coli blood-poisoning infections and deaths in humans resulting from the use of a third-generation cephalosporin in chicken production [1].

According to their analysis, chicken production is responsible for 1,580 cases of ESBL E. coli blood poisoning every year in the UK. These are serious infections requiring hospitalisation but can no longer be treated with the hospital antibiotics of choice, modern cephalosporins, because of prior use of similar antibiotics on farms.

The scientists say: ‘The number of avoidable deaths and the costs of health care potentially caused by third-generation cephalosporin use in food animals is staggering’. The study recommends that urgent worldwide action is taken to limit the use of these antibiotics in all food animals. The Soil Association has been calling for this since 2006.

Soil Association Policy Adviser, Richard Young, said; “This is the first detailed estimate to emerge of the human-health consequences from the use of antibiotics in European agriculture. It indicates that large numbers of people die of resistant infections due to the over-reliance on antibiotics in intensive livestock farming. It also shows that there are major additional costs to the NHS from treating patients even when they survive the infections.

This study relates to just one type of antibiotic and one bug in one type of animal – broiler chickens. However, the same type of antibiotics are also used in pig production and dairy farming, and the farm use of several other antibiotics also needs to be addressed because it gives rise to similar concerns.”

Since 2012, British poultry producers have voluntarily stopped using all cephalosporins in poultry [2]. The antibiotics were never licensed for use in poultry but were previously used ‘off-label’ for disease prevention in chicks. This practice was also widespread throughout Europe, despite technically being in breach of EU regulations, and in the Netherlands it led to ESBL E. coli being found on about 80% of retail chicken meat [3][4].

The Soil Association is concerned that at least two other types of antibiotics used in chicken production have the known ability to maintain ESBL E.coli on chicken farms, and that without action on these, the problem will persist, even though the use of cephalosporins has now been suspended.

Ends.

For press enquiries please contact:
Natasha Collins-Daniel, Press Office Manager – 0117 914 2448 / 07827 925380
ncollins-daniel@soilassociation.org

Holly Black, Digital Communications and Press Officer – 0117 314 5170
hblack@soilassociation.org

Additional information

The estimate of the number of deaths is based on published Dutch data showing that 56% of ESBL resistance genes in human E. coli are identical to genes found in E. coli from retail chicken [5]. Although the overlap between ESBL E. coli in humans and poultry may not be as high in the UK and some other European countries, the lack of adequate surveillance in most countries, including the UK, led the scientists to rely on the Dutch data [6]. The limited available evidence for the UK, which has previously been reviewed by the Soil Association, indicates that pigs and cattle could play a bigger part in this problem here while poultry may not be as significant as in the Netherlands.

ESBL E. coli are also spreading on pig and cattle farms, including in the UK, and there is evidence that the bacteria and their resistance genes can be exchanged between these animals and humans [7]. Defra research has shown that the practice of feeding untreated waste milk containing antibiotic residues to calves (which is not permitted on organic farms [8]) is contributing to the spread of ESBL E. coli on many dairy farms [9].

The use of cephalosporins in veterinary medicine has also led to the emergence of ESBL Salmonella and MRSA in farm animals, including in British livestock, with further consequences for human health [10].

Third-generation cephalosporins are classified by the World Health Organization as ‘critically important in human medicine’, and many scientists, including individual Defra and Health Protection Agency scientists, have recommended that their use in veterinary medicine should be limited [11]. Despite this, the use of these antibiotics in UK farming increased by 400% between 2000 and 2011, although it began to fall in 2011 [12].

One in ten of the current 39,000 E. coli blood poisoning infections in the UK are now resistant to third-generation cephalosporins [13].

The Soil Association wants to see decisive action to help reduce the levels of ESBL E. coli and other antibiotic-resistant bacteria on farms and in the food chain [14]. It runs on-farm workshops to show how farm animals can be kept in full health without routine use of antibiotics, and wants to help all farmers to move towards less intensive ways of keeping animals that are better for animal welfare and reduce the need for antibiotics.

Notes
[1] ESBL E. coli , Collignon et al. 2013, Human Deaths and Third-Generation Cephalosporin use in Poultry, Europe, Emerging Infectious Diseases, http://wwwnc.cdc.gov/eid/article/19/8/pdfs/12-0681.pdf
Appendix with data by country, http://wwwnc.cdc.gov/eid/article/19/8/12-0681-techapp1.pdf
The authors of the study include a World Health Organization adviser and government and other scientists from various countries.
[2] Cooper O., 2011. British Poultry Council to cut antibiotics, Farmers Weekly, 8 December 2011, http://www.fwi.co.uk/articles/08/12/2011/130475/british-poultry-council-drive-to-cut-antibiotics.htm
[3] Modern cephalosporins are not licensed for use in poultry, but unlicensed antibiotics can be used ‘off-label’ in certain circumstances at the discretion of a vet. Routine off-label use is not permitted, but in the past few years it has become apparent that many British and European hatcheries were injecting eggs or one-day old chicks with modern cephalosporins, in breach of regulations.
See p48 of EFSA Panel on Biological Hazards (BIOHAZ), 2011. Scientific Opinion on the public health risks of bacterial strains producing extended-spectrum β-lactamases and/or AmpC β-lactamases in food and food-producing animals, http://www.efsa.europa.eu/en/efsajournal/doc/2322.pdf
[4] Overdevest et al., 2011. Extended-spectrum β-lactamase genes of Escherichia coli in chicken meat and humans, The Netherlands, Emerging Infectious Diseases, http://wwwnc.cdc.gov/eid/article/17/7/pdfs/11-0209.pdf
Cohen Stuart et al., 2012. Comparison of ESBL contamination in organic and conventional retail chicken meat, International Journal of Food Microbiology, http://www.ncbi.nlm.nih.gov/pubmed/22260927
[5] It is also relevant that third-generation cephalosporins are normally only prescribed by vets for farm animals and hospital doctors in life-saving situations. They are not generally prescribed by GPs in the community. Despite this, many ESBL E. coli infections are of community origin. This is another reason why many scientists believe that farm animals, through the food chain and the environment are sources of the ESBL resistance in many human infections.
[6] The British Government recently announced funding for a study of ESBL E. coli in humans, animals, retail meat and the environment, but this will take three years to complete. https://www.gov.uk/government/news/new-study-to-give-insight-into-public-health-risks-of-esbl-e-coli
[7] Evidence that ESBL E. coli is present in farm animals and meat in the UK and abroad and can spread to humans is covered in Chapters 6 and 7 of the Soil Association’s report E. coli Superbugs on Farms and Food http://www.soilassociation.org/LinkClick.aspx?fileticket=yCT9su5iViQ%3d&tabid=1841
[8] In 2009, the Soil Association also introduced restrictions on the use of modern cephalosporins for the organic farms it certifies. Standard 10.09.08 reads, ‘From 1 January 2009 you must not use third and fourth generation cephalosporin antibiotics except with our permission and only to treat individual animals. We strongly recommend that you limit your use of these drugs before this date if possible.’
[9] http://registration.akm.ch/einsicht.php?XNABSTRACT_ID=140902&XNSPRACHE_ID=2&XNKONGRESS_ID=161&XNMASKEN_ID=900 and http://registration.akm.ch/einsicht.php?XNABSTRACT_ID=142425&XNSPRACHE_ID=2&XNKONGRESS_ID=161&XNMASKEN_ID=900
[10] According to Defra, ESBL resistance has spread to Salmonella in pigs: see point 2.4 of http://www.vmd.defra.gov.uk/pdf/darc_MinsAug10.pdf
MRSA is now widespread in pigs on the European continent (although not yet proven to be present in British pigs) and scientists suspect the use of modern cephalosporins is to blame, see:
http://www.octagon-services.co.uk/articles/cephalosporins.pdf
For evidence that MRSA is now present in British cattle see:
Paterson et al., 2012. First detection of livestock-associated meticillin-resistant Staphylococcus aureus CC398 in bulk tank milk in the United Kingdom, January to July 2012, Eurosurveillance, http://eurosurveillance.org/ViewArticle.aspx?ArticleId=20337
[11] Batchelor et al. 2005, Cephalosporin resistance among animal-associated Enterobacteria: a current perspective, Expert Review of Anti-Infective Therapy, http://www.ncbi.nlm.nih.gov/pubmed/?term=cephalosporin+resistance+among+animal-associated
[12] Statistics on modern cephalosporins have been obtained by the Soil Association from the Veterinary Medicines Directorate, and for more recent years are published in the VMD annual sales data reports available at http://www.vmd.defra.gov.uk/public/antimicrobial_pubs.aspx. Veterinary use increased from 220kg of active ingredient in 1999 and 2000, to a record 1,463kg in 2010, and then fell to 1,166kg in 2011. Use in 2011 was still the second highest level ever recorded.
[13] HPA data http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1317131223696 shows that there were 32,286 E. coli blood-poisoning infections in the 12 months to May 2013 in England. In Scotland in 2011, there were 3,839 E. coli blood-poisoning infections https://isdscotland.scot.nhs.uk/Health-Topics/Prescribing-and-Medicines/Publications/2013-02-26/2013-02-26-SAPG-Report.pdf?86452883482. Assuming that Northern Ireland and Wales have similar rates of infection, the total for the UK is about 39,000 cases. Data on resistance to third-generation cephalosporins is available here http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1317138991349
[14] The Soil Association is calling for an end to the use of modern cephalosporins in poultry and pig production, with their use in cattle being limited to serious infections shown, through sensitivity testing or other means, to be resistant to other antibiotics. Further action is also needed to find a way to prevent calves consuming high levels of antibiotic residues in waste milk.

 

 






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